Signaling system



Oct. 11,1927.

J. F. TOOMEY SIGNALING SYSTEM Filed Sept. 24, 1924 g I Ska/Release ATTORNEY Patented Get; 11, 1927.

JOHN F. TOOMEY', or new Yoiarcn. r, ASSIGNOR- To, enrnnroenrnnnrnonn Ann TELEGRAPH COMPANY, a conroae'rron or new roan.

, SIGNALING SYSTEM.

hApplication filed September 24, lea-i. SerialNo. 739,628. g

This invention relates to signaling systems, and more particularly to signaling systems adapted to be used in connection with railroad private branch exchange telephone circuits and railroad message and despatch circuits.

In railroad message and despatch systems, a plurality of way stations are connected at intervals with the lines and each station is provided with the customary selector and other apparatus. A comparatively high voltage is required for the operation of this apparatus, and heretofore it has been inex-,

pedient todirectly associate telephone private' branch exchanges with railroad message and despatch systems because of the detrimental effect such high voltage might have upon the equipment at the private 7 branch exchange. Accordingly, it is an object of this invention to associate a telephone private branch exchange with a railroad message and despatch system insuch manner as to eliminate any detrimental. 'efl'ect upon the private branch equipment by the high voltage required for the operation of the signaling apparatus, Other and further objects of the invention will be apparent from the following description, when read in connection with the accompanyingdrawing, in which appear certain embodiments thereof.' 7 r Referring to the drawing, Figure 1 represents a single railroad despatch or message circuit terminating at a telephone private branch-exchange; Fig. 2 indicates acircuit similar to Fig. 1 but adapted to be used with a plurality of despatch or message circuits. The equipment shown at the right of the vertical dotted linein each ofthe figures in the drawing is located at a terminal room from which a line extends to a plurality of way the left of said dotted line terminates at the private branch exchange.

In the drawing, in which like numerals designate like equipment throughout, 5 represents a plug of an operators cord circuit.

This plug is adapted tobe inserted in a jack 6, the tip and ring conductors'ofwhich extend to an outgoing line that may have a plurality o'f'way stations connected therewith, one of which is shown at 7. A connection may be completed from any of the way stations to a subscribers station over said line and the connectedcord circuit in a from ground, winding of relay 15to batstations. The equipment indicated at well-understood manner. A selector key 8 i is positioned at the private branch exchange which is adapted to selectively signal any desired "station connected with the outgoing I line. I In the'operation of this system, it will be assumed that a station connected with the line, for instance station 7, desires to call the private branch exchange operator. To do this, a hand generator 9, which is shown as bridged across the line,is operated and causes current to be transmitted over the conductors 10 and 11, through back contacts 'ofrelays'12 and 13 and windingof relay 1 1. The relay. 1% is normally bridged across the line conductors at the private branch exchange, and the closing of this circuit causes its'operation. The operation of relay 14 closes a circuit through its make contact, 7

5 tery,"thus causing the energization of relay 15, which in turn closes a circuit from the battery, winding of relay 16, make contact of relay 15 to ground, thereby operating relay 16. Theoperation of relay 16cl0ses a locking circuit through its winding and rightmake contact, from battery, back coni tact of relay 17 to ground. The operation of relay 16 also closes a circuit'through its left contact from ground, through filament of lamp 18 to battery, which causes the illui mination of this line lamp; The lighting of lamp 18 indicates to the attendantat the private branch exchange the presence of an I incoming call, and in response thereto, the

attendant will insert the plug of one of the toll. cords associated with the private branch exchange, such as 5, in th'ejack 6, thereby closing a circuit from battery, sleeve con-. tacts of said plug and jack, winding of relay 17 to ground. The closing of this circuit operates'relay 17, which inturn deenergizes relay 16 by opening its locking circuit, andv extinguishes the line lamp 18.- The operation of relay 17 closesa circuit through its 10 make contact from ground, conductor 19,- back contact of relayQO, conductor 21, winding of relay to; battery, thus causing the operation of the latter relay. Relay 13, upon operating, connectsthe calling station 7 over conductors 10 and 11 with theiprivate branch exchange, and also opens the circuit previously traced, whereby relay? 1 1 was operated when thisconnectionis established between the calling waystation 7 and 11 the private branch exchange conversation may be carried on between the two points, and the attendant at the exchange may complete over the cord circuit associated with jack 6 any connection desired by the way station.

It the private branch exchange operator wishes to call a way station on the message circuit, a plug of one of the toll cords is inserted in the jack associated with the line. For instance, plug 5 of the cord is inserted in the jack 6, thereby operating relay 1'? as formerly indicated, and the operation of this relay will. in turn cause the operation. of relay 13 and connect the line to the private branch exchange. At this time the attendant proceeds to set the selector key 8 for the code corresponding to the code which will operate the selector apparatus at the way station desired. The operation of the key 8 will send the proper code signals over the circuit comprising the conductors l0 and 11 in the usual manner. As soon as key 8 starts to operate, a circu t s closed from round, through a make rset. on the selector wheel. w nding ct relay 20 to battery. thus causing the o eration of this relay. The oper tion of relay 20 closes circ it thro gh its make conta t trom round. m e contact otrelav l7 conductors l9 and 22. throu h the wind n s ot rel ys l2 and 23 in paralle conductor 24 to bat e y The closu e ot th s ircu tcaus s he operat on ot rel s l2 and 23. The operat on ot re ay 25% connects the s nalling eouipment to the front c ntac s ot the relay l2. and the operat on ot the la ter rel y first opens the ine toward the private branch exchange. and then connec s t e hi h voltage sional n r npa t s to he ine o er con uctors .0 and The o e at n ot' relav 2 o ens the cu t o r la 13. caus n t to elease a d s o nect the line towards the private bra ch ex han e swi chboard.

Af er the s ector key 8 has been set. the operator causes its release in the usual manner o tha t returns to its normal position When the key releases it sends the number of impulses corresponding to the Position in which the key has been set. Thus when the key is released. its toothed wheel causes the normally open contacts to intermittently close a circuit from ground. conductor 25. winding otrelav 26 to battery which interm ttently energizes relay 26. lVhen relay 26. operates. it connects high voltage battery in one direction through its front contacts and make contacts of relays 23 and 12 to the line conductors 10 and ll. When relay 26 releases it connects the hi h. voltage current in the oppos te direction through its back contacts and make contacts of relays 23 and 12 to said conductors. This arrangement has the effect of sending a series of low-frequency impulses to the line, and

the selector apparatus at the called station corresponding to the code setting of key 8 will be operated in the customary and well understood. manner.

20 is designed to be slow releasing so that it will remain energized during the intermittent pulses which are sent out by the operation of the selector key 8. After the selector key 8 has returned to its normal po sition. the energizing circuit for relay 20 is automatically opened and this relay is caused to release. The release of relay 20 opens the circuit previously outlined through relays 12 and 23. causing these relays to release. When relay 12 releases, it connects the line to the contacts of relay l3, and this latter relay in turn is operated by the release of relay 20, which. through its back contact. connects ground from the back contact of relay 17 to battery through the winding of relay 13. Relays 17 and 13 are maintained operated while plug 5 is inserted in jack 6.

During the period the comparatively high volta e current s connected from the main batt ry throu h the contacts of relay 26 to o erate the selector apparatus at a way station. the line extending to the private branch exchan e w ll be open at contacts of relays 2 and l3. The opening-of this line at these two points protects the equipment at the pr va e b anch exchan e from any detrimental effects due to high voltage required for the ope at on ot the selector ap aratus op ected with the line extending to the way stations.

l'n the mo ficat on shown in Fig. 2. in wh ch more than one messa e circu t s involved. the selector key 8. instead of being permanently asso ated with a particular c rcuit. is arran ed so that it can. b means (it a cord and p us. be connected to any des red c u t. In or er to accomplish this. an add tional iack 27 is provided so that hen the plug 28 which is connected with the selector key 8. is inserted in the jack 27. it connects the term nals oi said key with the signalim equipment in a manner similar to that ou lined in-connection with Fig. 1.

In Fig. 2 the private branch exchan e is signalled and the selector apparatus at the way stations is operated as outlined in the description of Fig. 1. In like manner to Fig. 1 the circuit extending to the private branch exchange is opened at the contacts of relays 12 and 13 during the interval of operation of the selector apparatus to pro tect the equipment at said exchange from comparatively high voltage current.

hat is claimed is:

1. A signaling system comprising a private branch exchange, a line circuit ter minating thereat, a plurality of way stations associated with the line circuit, means at each way station for signaling the private branch exchange, means at the private branch exchange for selectively signaling the way stations, a relay controlled by said lastmeans, and relay means positioned at different points in the line circuit responsive to the operation of said relay for dissociating said privatebranch exchange from the line circuit at different points thereof during the interval of selective signaling.

2. A signaling system comprising a private branch exchange a line circuit terminating thereat, a plurality of way stations associated with the line circuit, means at each Way station for signaling the private branch exchange, switching means at the private branch exchange, a battery of com paratively high voltage, means for connecting said batteryto the line circuit for impressing thereon pulses of current predetermined by the switching means to selectively signal the way stations, arelay actuated by said switching means, and relay means positioned at different points in the line circuit controlled by said relay for disconnecting said private branch exchange from both sides of the line, circuit at a plurality of points thereof during the application thereto of the high voltage current. a

3. The combination of a telephone private branch exchange and railroad message circuits terminating thereat, a plurality of way stations associated with each message circuit, means at the way stations foreignaling the privatebranch exchange, means I at the private branoh exchange for selectively signaling the way stations associatetl branch exchange from the message circuit at a plurality of points during the interval of selective signaling. r

In testimony whereof, I have signed my name to this specification this 22nd dayot September "1924. p

i t JOHN F. TOOMEY. 

